Behavioral evidence suggests that instrumental conditioning is governed by two forms of action control: a goal-directed and a habit learning process. Model-based reinforcement learning (RL) has been argued to underlie the goal-directed process; however, the way in which it interacts with habits and the structure of the habitual process has remained unclear. According to a flat architecture, the habitual process corresponds to model-free RL, and its interaction with the goal-directed process is coordinated by an external arbitration mechanism. Alternatively, the interaction between these systems has recently been argued to be hierarchical, such that the formation of action sequences underlies habit learning and a goal-directed process selects between goal-directed actions and habitual sequences of actions to reach the goal. Here we used...

BACKGROUND: Accelerometry is rapidly becoming the instrument of choice for measuring physical activity in children. However, as limited data exist on the minimum number of days accelerometry required to provide a reliable estimate of habitual physical activity, we aimed to quantify the number of days of recording required to estimate both habitual physical activity and habitual sedentary behavior in primary school children.
METHODS: We measured physical activity and sedentary behavior over 7 days in 291 6- to 8-year-olds using Actigraph accelerometers. Between-day intraclass reliability coefficients were calculated and averaged across all combinations of days.
RESULTS: Although reliability increased with time, 3 days of recording provided reliabilities for volume of activity, moderate-vigorous intensity activity, and sedentary behavior...

Habitual dislocation of the patella (HDP) is a common presentation in pediatric age unlike adults. Many surgical procedures using proximal realignment and distal realignment have been reported to treat HDP in children with satisfactory results. However, late presentation of habitual patellar dislocation with osteoarthritis is rare and treatment plan has not yet been established. We present a case of neglected iatrogenic habitual patellar dislocation with osteoarthritis in a 50-year-old woman. Two-staged procedure was planned, first with patellar realignment and later with definitive total knee arthroplasty. Quadricepsplasty, medial patello-femoral ligament reconstruction, lateral release and tibial tuberosity transfer was done as primary procedure and total knee arthroplasty, which was planned as secondary procedure, was deferred as th...

Shifting between goal-directed and habitual actions allows for efficient and flexible decision-making. Here we demonstrate a novel, within-subject instrumental lever-pressing paradigm where mice shift between goal-directed and habitual actions. We identify a role for orbitofrontal cortex (OFC) in actions following outcome-revaluation, and confirm that dorsal medial (DMS) and lateral striatum (DLS) mediate different action strategies. In-vivo simultaneous recordings of OFC, DMS, and DLS neuronal ensembles during shifting reveal that the same neurons display different activity depending on whether presses are goal-directed or habitual, with DMS and OFC becoming more—and DLS less-engaged during goal-directed actions. Importantly, the magnitude of neural activity changes in OFC following changes in outcome value positively correlates with ...

Progressive loss of the ascending dopaminergic projection in the basal ganglia is a fundamental pathological feature of Parkinson's disease. Studies in animals and humans have identified spatially segregated functional territories in the basal ganglia for the control of goal-directed and habitual actions. In patients with Parkinson's disease the loss of dopamine is predominantly in the posterior putamen, a region of the basal ganglia associated with the control of habitual behaviour. These patients may therefore be forced into a progressive reliance on the goal-directed mode of action control that is mediated by comparatively preserved processing in the rostromedial striatum. Thus, many of their behavioural difficulties may reflect a loss of normal automatic control owing to distorting output signals from habitual control circuits, whi...

Twelve healthy, fully-dentate subjects participated in experiments which included the continuous recording of surface electromyography and jaw movement during habitual and deliberate right-sided or left-sided chewing of a coherent bolus. Analogue data streams were converted to digital values. Root-mean-square (r.m.s.) muscle-activity traces were computed from raw electromyographic data. The working side was defined as the side from which the mandible approached the position of occlusal stoppage when in the most cranially directed part of the chewing cycle. In any given muscle, greater mean peak r.m.s. activities were found with ipsilateral than contralateral bolus replacement (p &lt; 0.01, s); such differences were more pronounced for the masseter than the anterior temporal muscles. During habitual chewing, mean peak r.m.s. activities ...

In the present research the effectiveness of implementation intentions suppressing a habitual snacking response was investigated. Based on the literature on processing of negations and on thought suppression, it was expected that implementation intentions with an ‘if (situation), then not (habitual response)’ structure would, ironically, reinforce the habit one is trying to break. Using lexical decision tasks, it was shown that forming suppression implementation intentions results in (a) a heightened cognitive ‘situation- snack’ association, compared to an intention only control group (Studies 1 and 2) or compared to forming an implementation intention specifying the substitution of the habitual response with a new response (Study 3), and (b) a higher frequency and amount of eating unhealthy snacks (Study 3). Furthermore, Study 4 showe...

Previous studies have demonstrated that sleep duration is closely associated with metabolic risk factors. However, the relationship between habitual sleep duration and blood pressure values in Japanese population has not been fully established. We performed a cross-sectional study of 1,670 Japanese male subjects to clarify the relationship between habitual sleep duration and blood pressure values. The study subjects were divided into four groups (< 6, 6-, 7-, and a parts per thousand yen8 h) according to their nightly habitual sleep duration. The rate of subjects with < 6, 6-, 7-, and a parts per thousand yen8 h sleep duration was 12.0, 37.6, 38.2, and 12.2 %, respectively. Compared with the group with 7-h sleep duration (referent), the < 6 and a parts per thousand yen8 h groups had significantly greater systolic and diastolic blood pr...

Chronic alcohol misuse is an intractable problem for contemporary medicine. This paper explores some of the origins of this intractability, by examining the formulation of medical and moral models of habitual drunkenness during the nineteenth century. Its objective is to sketch out an historical perspective for contemporary problems in disentangling the relationship between culpability and susceptibility in alcohol dependence.

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